Acoustic device



Dec. 25, 1928.

O. E. BUCKLEY ACOUSTIC DEVICE Filed Nov. 29, 1926 Q. Sm

Patented Dec. 25, 1928.

' UNITED STATES vPATENT oFElcE.

OLIVER E. BUCKLI'Y, Ol' IAPLIWOOD, NEW JERSEY, ASSIGNOB TO BELL TELEPHONE moiwronms, Yoan.

IROOBPOBATED, l' NEW YORK, N. Y., A CORPORATION 0F NEW AGOUBTIC DEVIUI.

Application led Imker $9, 1928. Serial No. 151,299..

This invention relates to fluid wave systems and partcularl to systems or devices operated or controlled by acoustic waves.

An object of the invention is to convert oscillatory motion in 'a fluid into unidirectional motion'.

As ecific'object is to rovide a sensitive and e ective device by w 'ch electrical contacts may be operated in response to acoustic waves or other vibrational forms of energ.

In a preferred embodiment of lthe-invention there is provided a conduit lled withl air or other fluid and havin a constricted passage with which a secon municates. When oscillations are set up 1n the fluid contained in the first mentioned conduit by means of sound waves or other suitable driving force, the iuid is caused to move alternately in opposite directions through the constricted passage. -As the fluid passes through the constriction, its velocity is increased and its pressure is correspondingly reduced causing a suction of fluid from the second condui according to the well known principle o Bernoulli. The oscillatory motion of the fluid in the first conduit thus causes a unidirectional iow of iluidin the second conduit. When it is desired to obtain in this device relatively high eiciency for certain frequencies of oscillatory motion, a suitable resonant chamber is preferably connected to the first mentioned conduit through its constricted portion.

In accordance with another embodiment of the invention, a movable element such as a diaphra is provided to close a portion of the cont which communicates with the constricted passage of a second conduit. This diaphragm is employed to open or close electrical contacts associated therewith in response to the oscillatory ilow of fluid through the constricted passage. Such a device may be employed as a pneumatic relay in which sound waves impressed on the fluid in the second mentioned conduit cause the operation of an electrical contact.

In another aspect of the invention, an electromagnetic element is employed to drive a diaphragm which closes 'a portion of a conduit. The vibrations set up by the dia-V phragm due to alternating current flowing through the winding of the electromagnet, cause a reduction in fluid pressure in a second conduit ,communicating with the first. If

conduit lcomployed, as pointed out above, to open or close electrical contacts.

The invention may be readily undeistood byreterring to the followingA detailed descrlptlon and the accompanying drawing in which:

Fig: 1' is a sectional view of a pneumatic relay 1n accordance with this invention;

Fig. 2 shows a'modiication of the relay shown in Fig. 1, in which a resonant chamber 1s employed for increasing the sensitivity of the relay at certain frequencies; and

Fig. 3 shows another modification of the relay shown in Fig. l, in which valves are employed.

- Referring now particularly to Fig. 1 of the drawing, the chamber or conduit 10 containing air or other suitableI fluid leads through the constricted portion 11, into a reservoir containing the Huid, as for instance, the free atmosphere when air is employed as the fluid. The capillary tube 12 is attached tothe constricted portion 11 and communicates therewith through the small opening 13. This small opening oifers suilicient resistance to the How of fluid therethrough that the Huid flowing` in tube 12 is prevented from oscillating in response to the varying pressure in constriction 11. The other end of tube 12 is threaded into the casing 14, which is closed by the diaphragm 15 of conducting material to form a substantial air-tight chamber 21. The diaphragm 15 is clamped between the casing 14 and the clamping ring 16, the latter being insulated from the diaphragm by the insulating ring 17. The diaphragm 15 carries a contact element 18, which is normally in contact with the oppositely disposed adjustable contact 19, the latter being threaded through the projecting port-ion 23 of the conducting clamping ring 16.` A diaphragm 20 is employed to close a portion of the conduit 10, but it is not essential to the operation of the device.

In operation the Huid in conduit 10 is actuated either directly by sound waves or the passage for conducting the sound Waves to the constricted passage. The fluid flows back and forth through the constricted portion 11 at a substantially increased velocity and a decreased effective pressure. Consequently, the pressure of' the fluid in chamber 21 causes a flow. thereof into the constricted portion 11 and out through the opening 22. Due to the resulting decrease in pressure within the chamber 21, the pressure on the outside of the diaphragm 15 causes it to flex inwardly, thus breaking the connection between contacts 18 and 19 and opening the electrical circuit which may be connected therethrough.

The pneumatic relay shown in Fig. 2 differs from the relay of Fig. 1, in that the former is provided with an adjustable resonant chamber 25 and an electromagnetic receiver 40, which serves as a driving element. The chamber 25 communicates with the constricted portion 11 and is provided with a plunger 26, which may be moved by turning the thumb-screw 27 to change the edective length of the portion of the `cylinder' which communicates with the constricted portion. To obtain high sensitivity in`such a device, the plunger should be set so that the fluid moves at a maximum velocity through the constricted portion 11, when a current of the 'desired frequency is passed through the winding 28 of receiver 40. It is apparent that the device having the adjustablelresonant chamber may be employed, if desired, to operate only on a selected band of frequencies.

The relay of F ig. 3 comprises the chambers 30 and 31, which are connected by tube 32 through the valve 33. A portion of the chamber 30 is closed by the Idlaphragm 34, which may be set to vibration by acoustic waves or other suitable driving force. The valve 35 separates the chamber 34 from a large supply of the fluid employed in the device, as for instance, the free atmosphere when air is employed as the fluid. The chamber 31 is similar to the chamber 21 of the preceding figures, except that an opening' 36 ris provided for admitting fluid into the chamber 31. The size of this opening may be varied by turning the thumb-screw 37.

In the operation ofthis device, let it be assume-d that the diaphragm 34 is set into vibration by external means. When the diaphragm bows outwardly valve 35 closes and valve 33 opens. The volume of chamber 30 is conse uently increased and the pressure of the air t erein decreased, thus causing a flow of air from chamber 31 into chamber 30. When diaphragm 34 bows inwardly valve 33 is closed, valve 35, opened, and air forced out of the chamber 30 through valve 35. This operation continues as long as the diaphragm 34 is vibrating, thus resulting in a unidirectionallow of air from chamber 31 to chamber 30 and from the atmosphere into chamber 31 through opening 36. The size of the opening 36 is so adjusted, however, that the pressure in chamber 31 is decreased sufliciently while diaphragm 34 is vibrating to cause the separation of the contacts 18 and 19. When diaphragm 34 stops vibrating, air enters slowly through opening 36, thus increasing the pressure in chamber 31 to that of the atmosphere and causing the contacts 18 and 19 to be again restored to their normal or closed position.

For the best operation of the device, it is desirable that the moving parts of valves 33 and 35,be extremely light and that the naturall frequency thereof be well above the frequency at which the relay is operated. Sat-v isfactory results have been obtained by employing a valve of essentially the type shown 1n the drawing, using a very thin metal foil over the ends of small tubes. It is desirable, moreover, in order to secure the maximum pumping action that the ratio of the volume of chamber30 to thevolume changes caused by the movement of diaphragm 34 be as small as practicable. Y

It is to be understood that many embodiments of this linvention, other than the specific structures shown in the drawing and described herein, are included Within the scope of the invention. The structures shown are merely given as examples of devices made in accordance with the invention'and the drawing is merely schematic. It is apparent, moreover, that a device in accordance with this invention is operable at frequencies outside of the audible range. The term acoustic as used in this specification and the appended claims is, therefore, to be interpreted to include frequencies outside of the audible range.

What is claimed is:

1. An acoustically controlled device comprising constricted means for receiving acoustic waves, and means controlled there by for producing a uni-directional flow of fluid toward said constricted means.

2. In combination, a fluid conduit having a constricted portion, means for causing fluid to flow alternately through said constricted portion in opposite directions, and means associated with said constricted portion in which a uni-'directional flow of Huid is set up in response to said alternate flow.

3. In combination, a fluid conduit having a constricted portion` means for causing flui to flow alternately through said constricted portion in opposite directions in response to acoustic waves, and means associated with said constricted portion in which a unidirectional flow of fluid is set up in response to said alternate flow.

4. In combination, a fluid conduit having a constricted portion, 'vibratable means or causing fluid to flow alternately through said constricted portion Vin opposite directions, and means associated with said constricted portion in which a dow of lUU guid is set up in response to said alternate 5. In combination, a fluid conduit having a constricted portion, means for causing fluid to flow alternately through said constricted portion in opposite directions,and a second uid conduit communicatingwith said first fluid conduit through said constricted portion, the pressure of the fluid in said second fluid conduit being reduced by the difference in pressure of the alternate flow of fluid in said constricted portion.

6. In combination, a fluid conduit, a constricted portion forming a part thereof, a second flu-id conduit continuously communieating With `said first conduit through said constricted portion, and vibratable means associated With said first conduit for reducing the pressure in said second conduit.

7. In combination, a fluid conduit having a constricted portion, a second fluid conduit continuously communicating with said rst conduit through said constricted portion, and means closing a portion of said second conduit and operable in response to Wave energy set up in said first fluid conduit.

8. In combination, a fluid conduit having a constricted portion, a second fluid conduit continuously communicating with said first conduit through said constricted portion, and an electrical contact associated with said second conduit and operable in response to Wave energy set up in said first fluid conduit.

9. 'In combination, a fluid conduit having a constricted portion, vibratable means closing a portion of said fluid conduit, a second fluid conduit continuously communicating With said first conduit through said constricted portion, and means closing a portion of said second conduit andoperable in response to the vibrations of said vibratable means.

l0. In combination, a fluid chamber having a constricted passage, a second fluid chamber connected to said constricted passage and having an electrical contact associated there-v with, and vibratable means associated With said first fluid chamber causing the Withdrawal of fluid from said second fluid chamber toward said constricted passage thereby operating said electrical contact.

11. In combination, a chamber, a constricted passage forming a part thereof, a second "chamber communicating with said first chamber continuously through said constrict ed passage, a fluid in said chambers, a diasecond diaphragm being flexed in 4response v to pressure changes in said second chamber for operating said electrical contact.

l2. In combination, an air chamber, a constricted passage connecting said air chamber With the free atmosphere, a second air chamber communicating with said first air chaml ber through said constricted passage, a vibratable means associated with said first air chamber, for changing-the air pressure in said second air chamber, and movable means carrying an electrical contact and closing a portion of said second air chamber, said movable means being flexed in response to said pressure changes for operating said electrical contact. v

13. In combination, a fluid conduit, vibratable means associated there-With, a second fluid conduit resonant to the vibrations of said vibratable means, a constricted passage cpnnecting said conduits, a vthirdconduit connecting with said constricted passage in which a Vuni-directional iioiv of fluid is set up in response to the vibrations of said vibratable means.

14. In combination, a plurality of air chambers, vibratable means closing a portion of one of said chambers, a passage connecting said chambers, a second passage connecting said first chamber With the atmosphere, means for closing said `first passage in response to the movement of said vibratable means in one direction, and means for closing said second passage in response to the movement of said vibratable means in the opposite direction, the pressure in said second chamber being 'reduced in response to the vibration of said vibratable means.

In Vwitness whereof, I hereunto subscribe my name this 24th day of November A. D., 100

OLIVER E; BUCKLEY. 

